See also: Strain wave gearing - Wikipedia
First take the flex-spline:
Insert the output shaft from the backside:
Put in the spacer piece:
Mount the base of the wave generator:
Insert the 21 roller pieces:
Put on the cover on the wave generator:
Place the whole assembly in the housing:
Put on the lid:
Fix the lid using the 4 crews:
The author marked this model as their own original creation.